The primary objective of this study will be to investigate whether losartan (+ conventional therapy) compared to placebo (+ conventional therapy) will reduce the number of patients with NIDDM and early nepropathy who experience doubling of serum creatinine, ESRD (dialysis or renal transplantation) or death. The secondary objective will compare the effect of losartan to placebo on cardiovascular morbidity and mortality, proteinuria, and safety and tolerability. Teritary parameters include quality of life and health care resource utilization.